Optic fibers guide laser light from a first end of the optic fiber to a second end of the optic fiber. The light is maintained within the optic fiber due to total internal reflection that occurs at a boundary between a central core of the optic fiber and a surrounding cladding. This total internal reflection is caused by a difference in the index of refraction of the core relative to the cladding.
In some optic fibers, the laser light is emitted from the end of the optic fiber. In other optic fibers, the end of the optic fiber is altered so that light guided within the optic fiber is emitted from a side surface of the optic fiber. Typically, this alteration involves removing the cladding around the core at the end of the optic fiber and forming a total internal reflection surface on the end of the core. The total internal reflection surface is at an oblique angle to the axis of the optic fiber such that light from the optic fiber is reflected off the surface and out the side of the core. Such optic fibers are known as side-firing optic fibers.
The beam of laser light emitted by optic fibers of the prior art has a fixed diameter at a given distance from the optic fiber tip. This diameter is determined by the geometry and optics of the optic fiber.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.